Use of Methyldibenzothiophenes as Markers for Differentiation and Source Identification of Crude and Weathered Oils

Characterization of polycyclic aromatic sulfur heterocycles for source identification

“…However, there are indications that PASHs are resistant to water washing (Manowitz and Jeon, 1992) and therefore accumulate in water-washed oils. Although the mentioned results may seem contradictory, many reports in the literature indicate the usefulness of PASHs and their ratios to polycyclic aromatic hydrocarbons (PAHs) in oil spill source identification (see, for example, Wang and Fingas, 1995;Douglas et al, 1996) as discussed ahead.…”

“…It has been established that the ratio of the three GC peaks from the four methyldibenzothiophenes (2-and 3-MDBT coelute on nonpolar stationary phases) varies strongly with the source of a petroleum (Wang and Fingas, 1995). The ratio of 1-MDBT to 4-MDBT was plotted vs. the ratio of 2/3-MDBT to 4-MDBT for 25 oils and, as shown in Figure 4-7, a satisfactorily wide scattering was obtained, except for oils from the same fields (ibid.).…”

Identification and Linkage of Tarballs from the Coasts of Vancouver Island and Northern California Using GC/MS and Isotopic Techniques

“…(2) The relative ratios of the aliphatic compounds C 17 /pristane, C 18 /phytane, and pristane/phytane are almost identical for sample BC-1 and BC-2; These characteristic ratios have been found to be very useful markers for differentiating crude and weathered oils [20]. It has been demonstrated from the previous studies [20,38] that compared to most crude oils, the Bunker type fuels have a relative ratio of 2-/3-to 4-methyldibenzothiophene around 1.0, which is unusually high.…”

“…It has been demonstrated from the previous studies [20,38] that compared to most crude oils, the Bunker type fuels have a relative ratio of 2-/3-to 4-methyldibenzothiophene around 1.0, which is unusually high. These high ratios in the tarball samples provide further evidence that Bunker C was the original source oil.…”

“…In recent years, a number of diagnostic ratios of petroleum hydrocarbons have been proposed as indicators for weathering and biodegradation, and also for source identification [9,11,[18][19][20][33][34][35][36][37][38]. In addition to the conventional diagnostic PAH and biomarker ratios, several other "source-specific marker" compounds, especially the alkylated PAH hydrocarbons within homologous alkylation isomeric groups, were selected and their relative ratios were computed in this work, in order to definitively identify and differentiate the source(s) of the tarballs.…”